Process for synthesis gas production

Abstract

A process for obtaining a synthesis gas (GS) at a predetermined high pressure corresponding to the ammonia synthesis pressure, in which there are hydrogen and nitrogen in a 3 / 1 molar ratio, comprising the steps of feeding a continuous flow of natural gas to a primary reforming step (RP) with steam and to a subsequent secondary reforming step (RS) with excess air obtaining a gaseous flow (GF) comprises hydrogen, excess nitrogen with respect to said molar ratio, undesired substances such as impurities and inerts and subjects said gaseous flow to a purification step comprising cryogenic rectification in a separator unit (S) obtaining a continuous flow of synthesis gas (GS) comprising hydrogen and nitrogen in a 3 / 1 molar ratio, and to a subsequent compression step up to a pressure value required for ammonia synthesis.

Description

FIELD OF APPLICATION [0001] The present invention refers, in its most general aspect, to a process for synthesis gas production intended to produce ammonia in which a continuous flow of natural gas, for example methane, is subjected to a reforming step with steam (primary reforming), then to a reforming step with excess air (secondary reforming) and then to a purification step comprising cryogenic rectification of the gaseous flow produced in said secondary reforming step. [0002] In particular, the present invention refers to the cryogenic purification step of a process of the aforementioned type, to obtain pure synthesis gas at a predetermined pressure. PRIOR ART [0003] It is known that to obtain synthesis gas (H2+N2) intended for ammonia production, a continuous flow of natural gas, in particular methane (CH4), is subjected to reforming treatments, firstly with steam and then with excess air, called primary reforming and secondary reforming, respectively. [0004] The gaseous produc...

AI Technical Summary

Problems solved by technology

Such an essential recovery of pressure means a compression of the gaseous fluid from a particularly low pressure value, generally around 20 bar as determined by the aforementioned expansion, and this negatively influences the cost-effectiveness of the entire process.

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